JPH03289380A - Electrostatic actuator - Google Patents

Abstract

PURPOSE:To increase output/weight ratio and output/capacity ratio by forming both side parts of an electrode in an electrode supporter of an insulating material with its conductivity lower than the conductivity of a gap part between the electrode and a dielectric substance. CONSTITUTION:In the case of simultaneously applying voltage to adjacent paired electrodes 13a to 13f, 14a to 14f, each paired electrode 13a to 13f, 14a to 14f comes to give an influence by each other to a potential respectively in the vicinity thereof. Here a potential distribution curve by the paired electrodes 13a to 13f, 14a to 14f is difficult to extend to the adjacent paired electrodes 13a to 13f, 14a to 14f by forming both side parts of the electrodes 13a to 13f, 14a to 14f of an insulating material, whose conductivity is lower than the conductivity in a gap part between the electrodes 13a to 13f, 14a to 14f and dielectric substances 16a to 16f, in electrode supporters 13, 14 provided with the electrodes 13a to 13f, 14a to 14f.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention relates to an electrostatic actuator that uses electrostatic force to drive a load, particularly for industrial robots, precision instruments, The present invention relates to electrostatic actuators used to drive mechanical parts of automobile equipment parts, home appliances, OA equipment, medical equipment, etc.

(Prior Art) Servo motors have traditionally been used exclusively to drive the mechanical parts of industrial robots, precision machines, automobile equipment parts, home appliances, OA equipment, medical equipment, etc.

Magnetic actuators such as linear motors and stepping motors are used.

However, in recent years, there has been an increasing demand for actuators for driving mechanical parts such as those described above, which require higher output densities, more complex drive patterns, and control of minute displacements. However, conventional magnetic actuators are no longer able to satisfy all of these technical requirements.

Therefore, in recent years, electrostatic actuators with excellent output/weight ratios and output/volume ratios have been attracting attention as potentially satisfying the above technical requirements in place of magnetic actuators.

In this case, the electrostatic actuator is basically one in which a dielectric material (or electret) is arranged between multiple pairs of electrodes arranged to form a capacitor.
The structure is such that when a voltage is applied between the electrodes, a thrust is generated between the electrodes and the dielectric.

(Problem 8 to be Solved by the Invention) In the electrostatic actuator as described above, in order to obtain a predetermined output, it is necessary to independently obtain an arbitrary potential distribution for each electrode pair.

However, adjacent pairs of electrodes mutually influence the potentials in their respective vicinity when a voltage is applied. At this time, in particular, the potential distribution in the space between adjacent electrode pairs (the area where no electrode exists) is greatly affected, and in extreme cases, even though two or more electrode pairs are provided, one In some cases, only a potential distribution equivalent to that provided with a pair of electrodes can be obtained, and as a result, a predetermined output may not be achieved. Therefore, in order to prevent such a situation, it is necessary to set the distance between the electrode and the soil to a certain extent.

On the other hand, electrostatic force is more effective than electromagnetic force on a minute scale on the order of μm to nm, so electrostatic actuators must be extremely small. Furthermore, the thrust of the electrostatic actuator is approximately proportional to the number of basic unit actuators each consisting of an electrode pair and a dielectric.

Therefore, densely mounting electrode pairs in a small space is a key point in putting electrostatic actuators into practical use. However, as mentioned above,
In electrostatic actuators, it is necessary to set a certain distance between the electrodes and the ground, so it is impossible to densely package the electrode pairs in conventional electrostatic actuators, and this point remains an unresolved issue. It had become.

The present invention has been made in view of the above circumstances, and its purpose is to enable dense mounting of a large number of electrode pairs while obtaining an independent arbitrary potential distribution for each electrode pair. It is an object of the present invention to provide an electrostatic actuator that exhibits effects such as being able to increase the output/weight ratio and the output/volume ratio.

[Structure of the Invention (Means for Solving the Problems)] In order to achieve the above object, the present invention includes a plurality of pairs of electrodes arranged on an electrode support to form a capacitor, and a dielectric between these electrodes. In the electrostatic actuator, at least both sides of the electrode in the electrode support are formed of an insulating material having a conductivity lower than that of the gap between the electrode and the dielectric. It is.

(Operation) When voltages are simultaneously applied to adjacent pairs of electrodes, each pair of electrodes mutually influences the potentials in their vicinity. At this time, the electrode support on which the electrode is provided has at least both sides of the electrode in the gap between the electrode and the dielectric material (this is usually filled with an insulating gas or liquid or kept in a vacuum state). Since it is formed of an insulating material with a conductivity lower than the electric conductivity, it becomes difficult for the potential distribution curve of the electrode pair to extend to the adjacent electrode pair. As a result, the potential distribution curves of adjacent electrode pairs are separated from each other, and any potential distribution can be obtained independently for each electrode pair. Therefore, even when a large number of electrode pairs are densely mounted with a small distance between them, it is possible to ensure an independent arbitrary potential distribution for each electrode pair, and this makes it possible to improve the output/weight ratio and It is possible to increase the output/volume ratio.

(Embodiments) Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. First, the basic principle of each embodiment will be explained based on FIG. 4.

That is, FIG. 4 shows a schematic structure of the stator of the electrostatic actuator. In the same figure, a pair of electrode supports 1.2 arranged in parallel with a predetermined distance from each other include electrodes 3a, 3b and an electrode 4a.

Six pairs of electrodes 4b are supported and fixed so as to face each other, thereby forming electrodes 3a, 3b and electrode 4a.

Two capacitors are formed by six pairs of 4b.

In this case, as shown in FIG. 4(a), the electrodes 3B, 3b
By applying the output voltage of the DC power supply 5 between the electrodes 3a,
When the capacitor formed by 3b is charged, a potential distribution curve EP1 as shown by the broken line is obtained. Also, the fourth
As shown in Figure (b), a DC power source 6 is connected between the electrodes 4a and 4b.
When the capacitor formed by the electrodes 4a and 4b is charged by applying an output voltage of , a potential distribution curve EP2 as shown by a broken line is obtained.

However, when both the capacitors are charged simultaneously by the DC power source 5.6, the adjacent electrodes 3a.

Since the six pairs of electrodes 3b, 4a, and 4b mutually influence the potentials in their vicinity, the potential distribution of the area sandwiched between the six pairs of electrodes 3a, 3b, and 4a, 4b changes significantly. That is, in this case, as shown by the broken line in FIG. 4(c), the potential distribution curve EP3 is the same as if the two pairs of electrodes 3g, 3b and 4a, 4b were one electrode pair.
Therefore, it is not possible to obtain an independent potential distribution for each electrode pair.

This phenomenon occurs when the conductivity of the electrode supports 1 and 2 is lowered by the gap portion (filled with insulating gas or liquid This is thought to occur when the electrical conductivity is higher than that of the electrical conductivity of Therefore, Fig. 4(d), (e
), as shown in (f), instead of the electrode supports 1 and 2,
Electrode supports 1' and 2' made of an insulating material having a conductivity lower than that of the gap portion are used.

Then, in each case where the six pairs of electrodes 3a, 3b and 4a, 4b are individually energized, the result is shown in FIG. 4(d).

As shown by the broken line in (e), each potential distribution curve EPI
, EP2 becomes difficult to extend to the adjacent electrode pair, and the electrode 3a
, 3b and 4a, 4b, the potential distribution curves EPI and EP2 are separated from each other as shown by broken lines in FIG. 4(f).

As a result, adjacent electrodes 3a, 3b and 4a.

Even when six pairs of electrodes 4b are arranged close to each other, it is possible to form a substantially independent potential distribution for each pair of electrodes, and the present application is based on this phenomenon.

Now, FIG. 1 and FIG. 2 show a first embodiment of the present invention, which will be described below.

The first embodiment is shown in FIG. 4(d) above.

This is an extension of the basic principle structure shown in (e) and (f).

In FIG. 1, a stator 12 of an electrostatic actuator 11
A pair of electrode supports 13 and 14 are arranged in parallel with a predetermined distance from each other, and a pair of electrode supports 13 and 14 are supported and fixed in a row on each opposing surface of the electrode supports 13 and 14, respectively.
It is constituted by paired electrodes 13a to 13f and 14a to 14f.

As a result of this configuration, the electrodes 13a to 13f and 14a to
Each of the six pairs of 14f forms a capacitor.

Further, the movable element 15 of the electrostatic actuator 11 has a configuration in which six ferroelectric materials 16a to 16f are connected in a line with a predetermined distance from each other, and a load 17 is connected to one end of the movable element 15. Ru. The arrangement pitch of the ferroelectric materials 16a to 16f is the same as the electrodes 13a to 13f and 14a to 16f.
The pitch is set to be the same as the 6 pairs of 14f.

Therefore, in the electrode supports 13 and 14, the electrodes 13a to 13f, 14a to 14f and the ferroelectric material 16
a to 16f (that is, between the stator 12 and the mover 15), the insulation has a conductivity lower than that of the gap part (usually filled with an insulating gas or liquid or kept in a vacuum state). It is formed from a material (for example, quartz glass).

In the above configuration, with the mover 15 in the position shown in FIG.
When the output voltage of the DC power source 18 is applied to the pair and the capacitor formed by each electrode pair is charged, each ferroelectric material 16a to 16f of the movable element 15 acts in a direction that reduces the electrostatic energy of the capacitor. The position where the electrostatic energy is minimum (electrode 13a
~13f and each center of the ferroelectric materials 16a to 16f coincide with each other).

In this way, six of the electrodes 13a to 13f and 14a to 14f
If voltages are applied to the pairs simultaneously, each pair of electrodes will mutually influence the potentials of their respective neighbors. However, in the case of this embodiment, the electrodes 13a to 13f and 14a to 14f
The electrode supports 13 and 14 provided with the electrode 13a
~13f, 14a to 14f and the ferroelectric materials 16a to 16f are formed of an insulating material whose conductivity is lower than the conductivity of the gap between them. Therefore, the potential distribution curves of each of the above electrode pairs extend to the adjacent electrode pair. It becomes difficult to extend.

As a result, as shown by broken lines in FIG.
Potential distribution curve EP by 6 pairs of 3f and 14a to 14f
a-EPf are separated from each other, and as a result, any potential distribution can be obtained independently for each electrode pair. Therefore, a large number of electrodes 13a-13f and 14a to
Even when 6 pairs of 14F are densely mounted with a small distance between them, it is possible to ensure an independent arbitrary potential distribution for each electrode pair, and this allows the output/weight ratio and the output/weight ratio to be It becomes possible to increase the volume ratio.

Incidentally, according to the configuration of this example, compared to the conventional configuration in which the electrode support is made of an insulating material with relatively high conductivity,
Approximately twice the thrust was obtained.

In addition, when manufacturing the electrodes 13a to 13f and 14a to 14f, semiconductor manufacturing techniques such as lithography and thin film deposition method can be applied, making it possible to create an extremely small and precise integrated structure, which greatly reduces the overall size. Miniaturization can be achieved.

In addition, in the above embodiment, a plurality of electrets are provided in place of the ferroelectric materials 16a to 16f, and the conductivity of the member supporting each electret is configured to be lower than the conductivity of the gap portion between the electret and the electrode. You can also do it.

FIG. 3 shows a second embodiment of the present invention which has the same effects as the first embodiment described above, and will be described below.

That is, this example is characterized in that only the portions on both sides of the electrode in the electrode support are formed to have low conductivity. Specifically, one stator has three pairs of electrodes 20a to 20c and 21a to 21c arranged on each opposing surface of electrode supports 20 and 21 made of an insulating material. Electrodes 20a to 20c in
and electrodes 20a to 20 on both sides of 21a to 21C.
Highly insulating parts 20d to 20i and 21d made of an insulating material having a conductivity lower than that of the gap portion between C and 21a to 21c and a ferroelectric material (not shown) constituting the mover.
~21i is formed.

Also in this embodiment configured in this way, the electrodes 20a to
When a voltage is simultaneously applied to six pairs of 20c and 21a to 21c, the high insulation parts 20d to 20i and 21d to 21i
By providing the electrodes 20a to 20C,
And each potential distribution curve by six pairs of 21a to 21c is the third
As shown by broken lines in the figure, they are separated from each other, and the same effect as in the first embodiment is achieved.

[Effects of the Invention] According to the present invention, as is clear from the above description, in an electrostatic actuator in which a plurality of pairs of electrodes are arranged on an electrode support and a dielectric material is arranged between these electrodes, Since at least both sides of the electrode in the electrode support are formed of an insulating material having a lower conductivity than the conductivity of the gap between the electrode and the dielectric, a voltage can be simultaneously applied to a plurality of pairs of electrodes. Even in the case of high density electrodes, it is now possible to obtain an arbitrary potential distribution independently for each electrode pair, which makes it possible to realize dense packaging of many electrode pairs.
This has the excellent effect of increasing the output/weight ratio and the output/volume ratio.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a schematic side view of the whole, FIG. 2 is a schematic side view of a stator portion, and FIG. , FIG. 3 shows the second embodiment of the present invention.
FIG. 4 is a diagram corresponding to FIG. 2 for explaining the basic principle. In the drawing, 11 is an electrostatic actuator, 12, 19 are stators, 13, 14, 20, 21 are electrode supports, 13a to
13f, 14a ~ 14f, 20a ~ 20C, 21a
-21c are electrodes, 15 is a mover, 16a-16f are ferroelectric materials, 20d-20i, and 21d-211 are highly insulating parts.

Claims (1)

[Claims] 1. In an electrostatic actuator comprising a plurality of pairs of electrodes arranged on paired electrode supports to form a capacitor and a dielectric arranged between these electrodes, at least one of the electrodes in the electrode support An electrostatic actuator characterized in that both side portions are formed of an insulating material having a conductivity lower than that of the electrode and the gap portion between the dielectric.